Recent advances in portable computing includes the introduction of hand held electronic devices and computing platforms along the lines of the iPad™ tablet manufactured by Apple Inc. of Cupertino, Calif. These handheld computing devices can be configured such that a substantial portion of the electronic device takes the form of a display used for presenting visual content leaving little available space for an attachment mechanism that can be used for attaching an accessory device.
The display can include various user interface features that can interact with external stimuli to convey information from an end user, for example, and processing circuitry in the hand held computing device. For example, the display can include touch sensitive elements that can be used to enable various multi-touch (MT) functions. When the accessory device takes the form of a cover, the handheld computing device can be operable in modes consistent with the presence of the cover. For example, when the handheld computing device has a display, the presence of the cover can render the display unviewable. In order to save power, the unviewable display can be rendered temporarily inoperable until the cover is moved or otherwise repositioned to expose the display.
Therefore, accurate and reliable techniques for determining selected aspects of an accessory device are desired.